Caution: Is it really Alzheimer’s disease?
Up to 19% of patients misdiagnosed
It’s alarming but true. Studies show that 10% to 19% of all Alzheimer’s patients are misdiagnosed and, therefore, improperly treated. "There is still no blood test or scan that can confirm a diagnosis of Alzheimer’s. It’s a clinical rather than a conclusive diagnosis," says Marie Mangino, MSN, CRNP, president of Vincent Healthcare in Erdenheim, PA. "Biopsies done after death of presumed Alzheimer’s patients show that at least 10% were incorrectly diagnosed."
Although she finds Mangino’s figures a little high, Betsy Pegelow, RN, MSN, director of special projects at the Miami Jewish Home and Hospital for the Aged, agrees that misdiagnosis occurs. "Out of 700 patients entered into one of our Alzheimer’s projects, we know that five were misdiagnosed," she says. "In those five cases, the diagnosis was based on a family member reporting that the individual had difficulty remembering things, without any formal testing."
"When we sent the patients for formal testing by a neurologist, we found that they had other types of conditions unrelated to Alzheimer’s," says Pegelow. "Unfortunately, some physicians don’t feel it’s worthwhile to do extensive testing or any testing at all."
Case managers have a responsibility not to accept a diagnosis of Alzheimer’s without a thorough history and physical, Mangino says. "There are simply tons of other diagnoses than can be mistaken for Alzheimer’s, and many of them are easily reversed." Some of those diagnoses include:
• confusion due to medication reactions or interactions;
• lack of oxygen due to pneumonia;
• vitamin B12 deficiency;
• Parkinson’s disease;
• mild strokes, leading to vascular dementia;
• alcohol dementia;
• folate deficiency;
• electrolyte imbalances;
As case managers review the history of a presumed Alzheimer’s patient, they should look for documentation of the gradual progression of dementia, Mangino says. "Is the effect global or specific? Does it affect just memory in certain areas or global losses? If it is sudden in onset, it is more likely related to medication reactions. Dementia progresses slowly over months or years."
Ruling out alternatives
Any diagnosis of Alzheimer’s should include a thorough physical exam, a mental status exam, a neurological exam, and comprehensive laboratory tests, Mangino says. Some essential tests she recommends include:
• a complete blood count;
• a chemistry panel;
• VDRL for syphilis;
• HIV test, if risk factors exist;
• chest X-ray;
• CAT scan;
• ECG to rule out seizure disorder;
• drug and/or alcohol toxicity panel;
• neuropsychiatric testing;
"Elderly people who are borderline fragile can have a urinary tract infection and become confused," Mangino notes. "This is especially true of the frail elderly in nursing homes.
"Alzheimer’s has become a socially acceptable, even fashionable diagnosis. There is a predisposition to assume that any elderly person that shows confusion has Alzheimer’s. My message is that because there are so many treatable and/or reversible causes of cognitive impairment, we must take the time to thoroughly evaluate each patient and rule out all other potential causes before rendering a diagnosis of Alzheimer’s."